Ángel Guillermo "Memo" Heredia Hernández (born 12 February 1975) is a Mexican former discus thrower and sports coach known for his training expertise in boxing as well as his involvement in the BALCO scandal.
[4] Heredia struggled to break into the sport at a senior level and began doping with human growth hormone and testosterone.
[5] He won four discus titles at the Mexican Athletics Championships from 1995 to 1999,[6] but failed to achieve his dream of performing at the Summer Olympics.
He created a number of doping substances and methods, with a combination of testosterone, growth hormone and EPO being his most successful.
He began to work with boxers Juan Manuel Márquez and Jorge Arce in 2011, helping both to world titles.